1. Field of the Invention
The present invention relates to an apparatus for conducting continuous plasma treatment of long materials. More particularly, this invention relates to an apparatus for conducting continuous plasma treatment of long materials, such as membranes, films, sheets, fabrics, fibers or the like, particularly, long and flat materials which are relatively small in thickness and large in width (may be referred to as "treating material", hereinafter).
2. Description of the Prior Art
As an apparatus for plasma treatment, particularly, of flat sheet-like materials or long materials, a host of proposals heretofore have been made. For example, in Japanese Patent Application Publication Nos. 11,149/1985 and 31,939/1985, apparatuses for continuous treatment of fabrics with plasma by passing and treating the fabrics between a pair of parallel electrodes having a large surface area have been proposed. Further, in Japanese Patent Application Laid-open Nos. 60-134,061 and 61-228,028, and Japanese Patent Application Publication Nos. 59,251/1985 and 36,862/1986, apparatuses for plasma treatment having a plurality of antenna electrodes arranged around a cylindrical grounded electrode have been proposed. Furthermore, in Japanese Patent Application Publication Nos. 11,150/1985 and 54,428/1985, apparatuses for plasma treatment comprising multi-layered parallel plane electrodes provided up and down alternately for forming zigzag cloth passages have been proposed.
However, the proposals made in the above Japanese Patent Application Publication Nos. 11,149/1985 and 31,939/1985 have been involved in problems, such as uneven treatment caused by local deviations in degree of treatment over the large surface area of the electrodes and decrease in treating efficiency due to generation of plasma discharges in spaces on upper and lower sides and right and left sides of electrodes, or the like. Further, in the proposals made in the above-mentioned Japanese Patent Application Laid-open No. 60-134,061 and others, the treating area of the electrodes cannot be increased so much and discharge losses around antenna electrodes have been inevitable. In the proposals made in the above Japanese Patent Application Publication Nos. 11,150/1985 and 54,428/1985, lags in phase of high frequency are produced on the respective multi-layered electrodes whereby the high frequencies mutually interfere so that difficulties have been encountered in achieving operations and qualities with stability.
Thus, none of the hitherto known apparatuses for plasma treatment can completely satisfy all of the stability of operation, uniformity of quality and treating efficiency of input power.
We, the inventors, aiming at elimination of these problems and difficulties, proposed before, as Japanese Patent Application No. 62-171,464, an apparatus for plasma treatment which comprises a vacuum vessel, a plurality of antenna electrodes arranged therein having a curved treating surface bulging out with respect to the direction of the travel of treating materials, and grounded electrodes each arranged facing a treating surface of said antenna electrodes, and is provided with a guide means for passing said treating materials through gaps between said antenna electrodes and grounded electrodes. This proposed apparatus succeeded in solving various technical problems conventional apparatuses had been involved in. However, as a result of subsequent studies, the inventors have found the necessity of further improvements from aspects of compaction of apparatuses, increase in treating efficiencies, etc. and eventually accomplished the present invention.